/Engine/Source/Developer/ShaderFormatOpenGL/Public/ShaderFormatOpenGL.h
Final source code processing, based on device capabilities, before actual (offline) compilation; it mostly mirrors the behaviour of OpenGLShaders.cpp/GLSLToDeviceCompatibleGLSL()
[TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< ANSICHAR > PrepareCodeForOfflineCompilation ( [GLSLVersion](API\Developer\ShaderFormatOpenGL\GLSLVersion) ShaderVersion, EShaderFrequency Frequency, const ANSICHAR * InShaderSource ) const